Starry, an internet service provider (ISP) that promises to deliver super-fast internet access wirelessly, launched its first closed beta in the Boston area this week.

The company first announced its Starry Internet service at the beginning of this year, along with an intelligent router called the Starry Station that lets you easily manage your WiFi connections.

Starry’s CEO Chet Kanojia gave Business Insider a live demo of the service in action over a Skype chat. (Starry set up an apartment in the Somerville neighborhood of Boston for testing the service.) Kanojia showed that he was getting over 700 Mbps download speeds, which is several times faster than the speeds you probably get from your cable modem. It’s so fast that Kanojia was able to scrub through a streaming 4K video on a big-screen TV without any lag.

That’s something that consumers needed a fiber connection for until now.

However, don’t get too excited just yet. Starry’s beta is limited to a very small number of testers and won’t open as a public beta in Boston until early next year. And the company doesn’t plan to expand beyond Boston until we get well into 2017. Starry also won’t comment on how much its service will cost, only that it’ll be cheaper than a standard consumer connection today. It’s also unclear when the service will exit beta testing and be available to everyone.

Those are a lot of caveats! We’re clearly in the early days here, folks.

So, how does Starry work?

Starry plans to install transmitters called Starry Beams on top of building in urban areas. The Beams plug into fiber internet connections, just like the transmitters for wireless carriers do to deliver 4G data to your phone. But Starry Beam uses a different kind of frequency called millimeter wave that’s several times faster than 4G to a receiver in your home.

Those receivers are called Starry Points, and you install them in your window, kind of like an air conditioner. The Point then connects to your WiFi router, and you can use the internet normally from there.

Like we said, it’s clearly very, very early for Starry. And in the near future, it’ll have to grapple with rich companies like AT&T and Google that have similar ambitions to provide ultra-fast wireless internet as an alternative to traditional wired broadband.

In the meantime though, Starry’s beta is proof that such a service can work, and it’s a hint that one day internet access will only get easier, faster, and potentially more affordable.